The extracellular water insoluble polysaccharides play a significant role in the adherence of certain organisms to the surfaces of teeth. Purified glucans have been prepared enzymatically and their physical and chemical properties investigated. A study of the mechanism of synthesis indicated that glucose was not a free intermediate during the formation of glucan from sucrose by glucosyltranferase. SDS-Gel electrophoresis of the glucosyltransferases yielded six distinct subunits with molecular weights ranging between 23,000 to 130,000 daltons. The ability of dextrans, oligo and disaccharides to inhibit glucosyltransferase is being tested using an ultraviolet spectrophotometric assay and by measurement of radioactivity incorporated into insoluble polymer. The products formed in the presence of inhibitors are currently under investigation.